The present invention relates to an exhaust gas recirculation (EGR) system for an engine of a motor vehicle.
In an EGR system for an engine having an EGR port at the upstream side of a throttle valve at the closed position thereof, the amount of recirculated exhaust gas tends to be excessive when the engine is lightly loaded and inadequate when it is heavily loaded. Such a tendency is remarkable in the EGR system of an engine having a turbocharger.
Japanese Utility Model Laid-Open No. 53-35317 proposes a system wherein the amount of the recirculated exhaust gases is prevented from increasing during light and medium loads of the engine. However, the system has structural defects such as inversion of a diaphragm provided in an EGR valve.